To form interior walls, modern building methods typically employ sheets of drywall material nailed and/or screwed to wall studs. The joints between adjacent sheets of drywall material are covered with fabric tape and drywall mud. The taped and mudded seams are then sanded to obtain a relatively flat surface. The surface is then coated with a primer. The primed surface may be painted to obtain the finished wall surface, or texture material is often applied to the primed drywall surface before painting to create a textured surface pattern underneath the paint layer.
Texture material is a typically a paint-like coating comprising a base and a carrier. The base comprises a binder, a filler, and a pigment. Texture material also may contain other additives, such as thickeners, surfactants, defoamers, preservatives, and the like, depending upon the application methods and destination surface. The carrier allows the base to be deposited on the destination surface in a liquid form. When exposed to air, the carrier evaporates, and the binder adheres the filler and pigment to the destination surface. The characteristics of texture material are such that the dried texture material is not smooth like paint but instead creates a bumpy, irregular texture on the destination surface.
Texture materials can be applied to a destination surface in a number of different ways. For large surface areas, the texture material is typically applied with a sprayer system. Sprayer systems may be airless or may mix the texture material with a stream of pressurized air. The source of pressurized air may be a compressor, storage tank, or hand operated pump.
In other cases, such as touch up or repair of a wall or ceiling surface, only a small area need be covered with texture material. For small surfaces areas, the texture material is preferably dispensed using an aerosol system. Aerosol systems typically employ a container assembly, valve assembly, nozzle assembly, and propellant. The propellant pressurizes the texture material within the container such that, when the valve is opened, the texture material flows out of the nozzle assembly. The nozzle assembly is typically designed to deposit the texture material on the destination surface in selected one of a plurality of predetermined texture patterns.
The present invention is of particular relevance to the application of a specific type of texture material often referred to as acoustic or “popcorn” texture material to small surface areas, and that application will be described herein in detail. Acoustic texture material contains, in addition to a carrier and base, what will be referred to herein as a “particulate” material. The particulate material is typically formed by polystyrene chips, but other materials, such as cork, rubber, or the like, may also be used. Typical particulate materials exhibit desirable sound absorption qualities that give acoustic texture material its name.
With sprayer systems, the dispensing of acoustic texture material containing particulate material does not typically pose a problem. However, the composition of the particulate material has limited the use of aerosol systems to apply acoustic texture materials.
In particular, common aerosol propellants tend to dissolve polystyrene and thus are incompatible with the most common type of aggregate used in acoustic texture materials. Inert compressed gasses such as compressed air have been successfully used as a propellant for acoustic texture material in an aerosol system. However, the use of compressed inert gas as a propellant yields a stream of texture material that is relatively difficult to control. In addition, the polystyrene chips travel at relatively high speeds that can cause the chips to bounce off of the destination surface.
The need thus exists for improved systems and methods for applying acoustic texture material to relatively small surface areas.